The invention relates to a flame-type heater plug for an air-compression fuel-injection internal-combustion engine.
Under specific conditions, during starting the fuelinjection internal-combustion engines which work on the auto-ignition principle require starting aids in order to raise the final compression temperatures to values above the auto-ignition temperature.
Known flame-type heater plugs (FIG. 8) used as a starting aid during the starting operation consist essentially of a plug housing with a flame tube, a proportioning insert, a heating bar and an evaporator tube surrounding the heating bar. The fuel supplied via the proportioning insert passes into an annular interspace between the heating bar and evaporator tube and from there flows into the flame tube where it mixes with the inflowing air.
In designs of this type, it has been shown that the fuel introduced is not always evaporated sufficiently or is evaporated only partially, thus impairing the ignition of the fuel.
An object on which the invention is based is, by means of simple constructional variations on the flametype heater plug referred to above, to prepare the fuel in such a way that it experiences the best possible evaporation and forms an ignitable mixture with the air penetrating into the flame tube.
The present invention achieves this object by providing an arrangement wherein a fuel connection includes a helical swirl channel opening into the annular interspace and located between the plug housing and the heating bar.
The special fuel connection between the proportioning insert and the evaporator tube ensures a substantially better evaporation of the fuel in the narrow helical swirl channel, from which the fuel emerges swirling and, accelerated by the annular interspace, enters the flame tube and there mixes with the inflowing air to form the best possible fuel/air mixture
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings.